Feat of clay: From soil to super material

By Jon Cartwright

The stuff of pottery and piggy banks can be transformed into a nanocomposite that is stronger than steel, light as plastic and cheap as mud

JULIAN EVANS leans back on his chair in the chemistry department of University College London. For the past hour or so we have been discussing a new wonder material, and now it’s time for me to see it for myself. He shows me a close-up picture of a sample. It looks like the plastic wrapping on a pack of supermarket fruit. “It’s see-through,” I observe, surprised.

Lots of materials are transparent, of course, but they are rarely noted for their strength. Yet this stuff is stronger than steel, and perhaps even a match for Kevlar, the material used in bulletproof vests. It’s also as light as plastic yet as stiff as carbon fibre.

This stuff is perhaps even a match for Kevlar, which is used in bulletproof vests

Perhaps the most surprising thing is that it is made from clay – the same stuff we use to make bricks and crockery and which sticks to your spade as you dig your garden. But treated in the right way, clay’s properties can be transformed. It is also dirt cheap. “All you need is to pull it out of the ground and wash it,” Evans says.

This is music to the ears of aircraft and car manufacturers, who are crying out for alternatives to steel and aluminium. At the moment their best option is carbon fibre composite. This is a great material – Volkswagen, for instance, has used it to achieve astonishing levels of fuel …

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